1. Field of the Invention
This invention relates to reactors for conducting polymerization of monomers, and in particular, bulk polymerization reactors for conducting polymerization of alpha-olefin monomers.
2. Description of Related Art
Formation of polymers from various monomers is a well-known art. As is also well known in the art, the polymerization reactor in which the polymers are formed from the monomers have certain inherent limitations to efficiently form the polymers. A major inherent limitation is the removal of heat from the polymerization reactor created by the chemical reaction between the monomers and the catalyst during formation of the polymers. To overcome this problem, cooling systems have been designed to encase the polymerization reactor in an attempt to remove the heat from the polymerization reactor. Additionally, cooling additives may be included in the polymerization reaction mixture in the polymerization reactor.
Both of these prior attempts, however, have various shortcomings. For example, the use of cooling systems outside the polymerization reactor do not efficiently and effectively remove heat from the polymerization reactor, especially for the center most region of the polymerization reactor. Accordingly, the size of the polymerization reactor must be small and limited amounts of polymer may be formed in each reactor batch. Additionally, with respect to the addition of cooling additives to the polymerization reactants, these cooling additives can have an adverse effect on the quality of the polymer as well as increasing the cost associated with forming the polymer.
In other prior attempts, as discussed in U.S. Pat. Nos. 5,449,732, 5,504,131, and 5,504,132, the polymerization reactor is a crystalline, hydrocarbon-insoluble organic polymer reaction enclosure capable of substantially preventing passage of oxygen and water, i.e., plastic bags. Use of these plastic bags permits the polymerization reaction to be carried out without a cooling system or addition of cooling additives. However, because the plastic bags are not provided with any assistance in the removal of heat from the polymerization reaction, only small amounts of polymer reactants, e.g., monomer and catalyst, can be included in each plastic bag. As such, only small amounts of polymer can be formed in each of this type of polymerization reactor. Further, the plastic bags can not be easily separated from the polymer, and thus, are not re-useable.
Accordingly, prior to the development of the present invention, there has been no polymerization reactor or process for forming polymers, which: effectively remove heat away from the polymerization reactor; permit the formation of a large amount of polymer in each polymerization reactor; do not require the addition of cooling additives; and permit the use of a re-useable polymerization reactor. Therefore, the art has sought a polymerization reactor and a process for forming polymers, which: effectively remove heat away from the polymerization reactor; permit the formation of a large amount of polymer in each polymerization reactor; do not require the addition of cooling additives; and permit the use of a re-useable polymerization reactor.